Mobile communications radio receiver for multiple network operation

ABSTRACT

A mobile communications radio receiver for multiple radio network operation includes an RF unit for generating a first down-converted signal from a radio signal received from a first radio network and a second down-converted signal from a radio signal received from a second radio network. Further, the receiver includes a first receiving unit including a user data channel demodulator configured to demodulate a dedicated user data physical channel and a control channel demodulator configured to demodulate a common control data channel of the first radio network based on the first down-converted signal. Still further, the receiver includes a second receiving unit including a pilot channel demodulator configured to demodulate a pilot channel of the second radio network based on the second down-converted signal. A first data connection is configured to couple control data contained in the second down-converted signal to the control channel demodulator of the first receiving unit.

REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. application Ser. No. 13/106,925filed on May 13, 2011.

FIELD

The invention relates to mobile communications, and more particularly tothe technique of receiving and processing signals from multiple radionetworks.

BACKGROUND

A new feature for receivers in mobile communications isDual-SIM-Dual-Standby (DSDS). It means the UE (user equipment) contains(at least) two SIM (subscriber identity module) cards and registers in(at least) two radio networks. If the UE is in an idle/standby state, itshall be able to receive pagings, i.e. notifications of incoming callsor messages, from both networks.

Another feature for a Dual SIM (DS) phone is to receive a paging on onenetwork during an active connection (e.g. call) on the other network.This feature will be referred to as Dual-SIM-Single-Transport (DSST) inthe following.

Still another challenging feature for a DS phone is to have at least twoactive connections (e.g. calls) in parallel, possibly on two differentradio networks. This feature will be referred to asDual-SIM-Dual-Transport (DSDT) in the following.

A straight-forward approach to have two active connections is to add acomplete second receiver chain to the UE. However, this means additionalhardware, implying additional chip area and power consumption.

For these and other reasons there is a need for improvements in mobilecommunication devices and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of embodiments and are incorporated in and constitute partof this specification. The drawings illustrate embodiments and togetherwith the description serve to explain principles of embodiments. Otherembodiments and many of the intended advantages of embodiments will bereadily appreciated as they will become better understood by referenceto the following detailed description. Like reference numerals designatecorresponding similar parts.

FIG. 1 is an illustration of a first multiple network scenario for amobile communications radio receiver.

FIG. 2 is an illustration of a second multiple network scenario for amobile communications radio receiver.

FIG. 3 is block diagram illustrating an embodiment of a mobilecommunications radio receiver.

FIG. 4 is block diagram illustrating an embodiment of a mobilecommunications radio receiver.

FIG. 5 is block diagram illustrating an embodiment of a mobilecommunications radio receiver.

FIG. 6 is a flowchart of an embodiment of a method of demodulating userdata of two radio networks in a mobile communications radio receiver.

FIG. 7 is a timing diagram illustrating a first scenario of continuouspacket connectivity on a first network and a second network.

FIG. 8 is a timing diagram illustrating a second scenario of continuouspacket connectivity on a first network and a second network.

FIG. 9 is a timing diagram illustrating a third scenario of continuouspacket connectivity on a first network and a second network.

FIG. 10 is block diagram illustrating an embodiment of a mobilecommunications radio receiver.

FIG. 11 is a flowchart of an embodiment of a method of demodulating asignal transmitted by a second network while having a discontinuousreception continuous packet connection established with a first network.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part thereof, and in which are shownby way of illustration specific embodiments in which the invention maybe practiced. In the drawings, like reference numerals are generallyutilized to refer to like elements throughout the description. In thefollowing description, for purposes of explanation, numerous specificdetails are set forth in order to provide a thorough understanding ofone or more aspects of embodiments of the invention. It may be evident,however, to one skilled in the art that one or more aspects of theembodiments of the invention may be practiced with a lesser degree ofthese specific details. In other instances, known structures and devicesare shown in a simplified representation in order to facilitatedescribing one or more aspects of the embodiments of the invention. Thefollowing description is therefore not to be taken in a limiting sense,and the scope of the invention is defined by the appended claims.

The various aspects summarized may be embodied in various forms. Thefollowing description shows by way of illustration various combinationsand configurations in which the aspects may be practiced. It isunderstood that the described aspects and/or embodiments are merelyexamples, and that other aspects and/or embodiments may be utilized andstructural and functional modifications may be made without departingfrom the scope of the present disclosure. In particular, it is to beunderstood that the features of the various exemplary embodimentsdescribed herein may be combined with each other, unless specificallynoted otherwise.

As employed in this specification, the terms “coupled” and/or“electrically coupled” are not meant to mean that the elements must bedirectly coupled together; intervening elements may be provided betweenthe “coupled” or “electrically coupled” elements.

The mobile communications radio receiver described herein will bereferred to as UE (user equipment) and may be employed in terminaldevices of wireless communication systems, in particular in mobilephones or other mobile terminal devices.

By way of example, FIG. 1 illustrates a first multiple network scenariofor a mobile communications radio receiver (UE). The UE is configured toregister in two networks NW1 and NW2. In this embodiment, the networksNW1 and NW2 are operated on different frequency bands f1 and f2. Thus,since the UE must be available to receive pagings from the NW1 operatorand the NW2 operator, the UE must be able to tune to frequency bands f1and f2. By way of example, as shown in FIG. 1, different base stationsB1, B2 (i.e. different cells) may be used by the networks NW1 and NW2.However, it is also possible that networks NW1 and NW2 use shared basestations, wherein B1=B2 (i.e. the same cells).

FIG. 2 illustrates a second multiple network scenario for an UE. The UEis configured to register in two networks NW1 and NW2. In contrast tothe scenario illustrated in FIG. 1, the networks NW1 and NW2 areoperated on the same frequency band f1. Thus, the UE is available toreceive user data (e.g. a voice signal, a data signal etc.) from the NW1operator and the NW2 operator if tuned to frequency band f1. By way ofexample, as shown in FIG. 2, different base stations B1, B2 (i.e.different cells) may be used by the networks NW1 and NW2. However, it isalso possible that networks NW1 and NW2 use shared base stations,wherein B1=B2 (i.e. the same cells).

Throughout this description, the signals received from the first andsecond networks NW1, NW2 are different, i.e. they contain differentinformation.

FIG. 3 is a block diagram illustrating an embodiment of an UE 100. UE100 comprises an RF unit 1, a first receiver 20 for demodulating a firstdown-converted signal S1 from a radio signal received from the firstradio network NW1 and a second receiver 30 for demodulating a seconddown-converted signal S2 from a radio signal received from the secondradio network NW2. The first receiver 20 comprises, inter alia, acontrol channel demodulator 2 which may be operated to demodulate acommon control channel (e.g. the first and/or second common controlchannels PCCPCH, SCCPCH) of the first radio network NW1 based on thefirst down-converted signal S1.

In this embodiment, the control channel demodulator 2 of the firstreceiver 20 is connected by a data connection 4 to signal S2 whichcontains the common control channel signal of the second network NW2.This allows for resource sharing between the first and second receivers20, 30. More specifically, during DSDT, when there is an activeconnection established on network NW1, i.e. the first receiver 20 isactive to demodulate e.g. speech data of a call on network NW1, thecontrol channel resources for demodulating the common control channel(s)of network NW1 of the first receiver 20 are not used continuously.Therefore, the control channel demodulator 2 of the first receiver 20may be used to demodulate the common control channel signal of thesecond network NW2 received via data connection 4. In other words, thesignal which contains the common control channel of the second networkNW2 is routed via data connection 4 to the control channel demodulator 2of the first receiver 20. Thus, common control data on the secondnetwork NW2 may be detected in the first receiver 20. Note that thefirst receiver 20 may be a full HSUPA (High Speed Uplink Packet Access)receiver which has a common control channel demodulator 2 and the secondreceiver 30 may be a reduced HSUPA receiver which has no common controlchannel demodulator. Together, receivers 20 and 30 may be adual-cell/dual-band HSUPA receiver.

By way of example, if the first receiver 20 has no spare or unusedcontrol channel demodulator 2 during an active connection on the firstnetwork NW1, the control channel demodulator 2 of the first receiver 20may be operated in time multiplex to alternatingly demodulate a commoncontrol channel of the first network NW1 and a common control channel ofthe second network NW2. That way, it is possible to have two activeconnections in parallel. Possible cases are, e.g., to have a voice planon the first network NW1, a data plan on the second network NW2 and todo the voice call on NW1 concurrently with the data connection on NW2.

If two (or more) active connections are processed on the UE 100, thepossibility of conflicts due to requests overlapping in time exists. Inthis case, a priority decision may be taken, e.g., based on usersettings or network settings. By way of example, the priority decisionmay be based on the number of repetitions and/or the length of therepetition interval of the critical information sent on the firstnetwork NW1 and/or the second network NW2 to UE 100. As criticalinformation such as e.g. a message or control information needed tomaintain the active connection is usually repeated (e.g., it may beretransmitted if receipt thereof is not acknowledged by the UE 100), thechance is high that, e.g., missing one message or control informationdue to a conflict does not lead to a loss of connection because themessage or control information is repeated.

Thus, depending on the priority settings, either the active connectionon the first network NW1 or the active connection on the second networkNW2 may be prioritized, and in both cases both operations could beperformed (even though the non-prioritized operation may be delayed fora specific time). The priority setting (common control channeldemodulation of the first or second network NW1 or NW2 prioritized) maybe adapted on the basis of the settings of the two networks NW1, NW2.

FIG. 4 illustrates a more detailed block diagram of one embodiment of UE100. By way of example, the RF unit 1 may comprise two RF stages 1.1 and1.2. The RF stages 1.1 and 1.2 may be tuned to different frequency bandsin one embodiment. RF stage 1.1 comprises an RF down-converter andprovides the first down-converted signal S1 from a radio signal receivedfrom network NW1 and RF stage 1.2 comprises an RF down-converter andprovides the second down-converted signal S2 from a radio signalreceived from network NW2. Thus, different down-conversion frequenciesmay be concurrently used in the RF stages 1.1 and 1.2, respectively. TheRF unit 1 may, in one embodiment, be used in a dual-cell/dual-bandenvironment using different frequency bands for transmissions ofnetworks NW1 and NW2 as shown in FIG. 1.

FIG. 4 further illustrates a block diagram of the first and secondreceivers 20 and 30 contained in UE 100, respectively. As mentionedearlier in conjunction with FIG. 3, the UE 100 may contain a first ormain receiver 20 and a second or reduced receiver 30. The main receiver20, which may be, in one embodiment, an UMTS Rel99 receiver, maycomprise a number of demodulators, e.g. a CPICH (Common Pilot CHannel)demodulator 21 for pilot demodulation, a PICH (Paging Indicator CHannel)demodulator 22, a PCCPCH (Primary Common Control Physical CHannel)demodulator 2.1, a first SCCPCH (Secondary Common Control PhysicalCHannel) demodulator 2.2 for control data demodulation such as, e.g.,PCH (Paging CHannel) demodulation in case a PI (Paging Indicator) isdetected by the PICH demodulator 22, a second SCCPCH demodulator 2.3, aDPCH1/FDPCH (Dedicated Physical CHannel/Fractional Dedicated PhysicalCHannel) demodulator 25, two additional DPCH demodulators 26, 27 and anHSUPA (High Speed Uplink Packet Access) demodulator 28 demodulating thecorresponding RGCH (Relative Grant CHannel), HICH (Hybrid ARQ IndicatorCHannel) and AGCH (Absolute Grant CHannel).

The reduced receiver 30 may contain a number of demodulators which areneeded for dual-carrier HSUPA capability, namely a CPICH demodulator 31for pilot demodulation, a FDPCH demodulator 32 and an HSUPA demodulator33 demodulating the corresponding RGCH, HICH and AGCH.

It is to be noted that in HSUPA uplink data is transmitted on twodifferent carriers. Thus, to receive the corresponding (different) HSUPAcontrol channels, an UE having HSUPA capability needs a second receiver.To limit semiconductor chip area and power consumption, the secondreceiver may be stripped down to the functions necessary for thedemodulation of the HSUPA control channel on the second carrier. Thereduced receiver 30 shown in FIG. 4 is such a second receiver configuredfor HSUPA control channel demodulation. Note that in one embodiment,this reduced receiver 30 may not contain any DPCH demodulator, since onthe second carrier no Rel99 data downlink channel DPCH exists. However,it must include a FDPCH (fractional DPCH) demodulator 32. Further, inone embodiment, the reduced receiver 30 does not include a PCCPCH and/ora SCCPCH and/or a PICH demodulator, see UE 100 shown in FIG. 4. This mayalso apply to the UE 100 illustrated in FIG. 3.

Further, the UE 100 in one embodiment may contain only one single mainreceiver 20 employing, e.g., demodulators 21, 22, 25, 26, 27, 28, 2.1,2.2, 2.3 and only one single reduced receiver 30 employing, e.g.,demodulators 31 to 33.

Similar to the illustration in FIG. 3, a data connection 4 is used toroute signal S2, which contains the PCCPCH, the SCCPCH and the DPCH onthe second network NW2, to the main receiver 20, and, more specifically,e.g., to the inputs of the PCCPCH demodulator 2.1, the SCCPCHdemodulator 2.2 and the second DPCH demodulator 26 (referred to asDPCH2), respectively.

In one embodiment, the DPCH2 demodulator 26 of the main receiver 20 maybe used to demodulate the DPCH of the second radio network NW2 (notethat the FDPCH demodulator 32 in the reduced receiver 30 is not operableto demodulate a DPCH). This second DPCH demodulator 26 (as well as athird DPCH demodulator 27 referred to as DPCH3) may exist in the mainreceiver 20 due to the so-called multicode feature stipulated in theUMTS (Universal Mobile Telecommunications System) specifications, wherean active connection may be assigned up to three DPCHs to increase thedata rates. However, with the introduction of HSDPA (High Speed DownlinkPacket Access), this feature is not or only very rarely used any more.Therefore, one of the spare DPCH demodulators 26, 27 in the mainreceiver 20 may be used to demodulate the DPCH of the second radionetwork NW2.

Since the main receiver 20 is operating an active connection, e.g., acall, on the first network NW1 (i.e. the DSDT case is considered), theremay not be any completely unused common control channel demodulationresources in the main receiver 20 to be used for demodulating thecorresponding channels (e.g. PCCPCH, SCCPCH, etc) of the second radionetwork NW2 (which can not be demodulated in the reduced receiver 30because appropriate demodulators operable to demodulate these channelsare missing in the reduced receiver 30). However, as described above, atime multiplexing of one or more of these common control channeldemodulators between down-converted signal S1 and down-converted signalS2 (coupled to the main receiver 20 via data connection 4) is possible.

The second or reduced receiver 30 may comprise a channel estimator togenerate channel estimates based on the second down-converted signal S2.Here, by way of example, the CPICH demodulator 31 may be used as channelestimator. Thus, at an output of the CPICH demodulator 31, channelestimates indicative of the channel characteristics of the communicationlink associated with the second network NW2 are provided. These channelestimates are routed via a data connection 5 to the main receiver 20.

The channel estimates generated in the reduced receiver 30 and providedvia data connection 5 may be input to the PCCPCH demodulator 2.1 and/orthe PCCPCH demodulator 2.2 and/or the DPCH2 (or DPCH3) demodulator 26(or 27) of the main receiver 20 in order to demodulate the PCCPCH and/orthe SCCPCH and/or the DPCH on the second carrier (second network NW2).This is possible since these resources are either time-multiplexed orunused during DSDT in UE 100. When rerouting the common control channelinformation and/or user data of the second network NW2 to thetime-multiplexed or unused demodulators 2.1, 2.2, 26, 27 in the mainreceiver 20, the outputs of these demodulators 2.1, 2.2, 26, 27 have tobe interpreted by downstream decoder circuitry (only exemplarily shownfor DPCH demodulators 25, 26, 27) to be indicative of the correspondingcontrol channel information or user data on the second network NW2rather than on the first network NW1.

As known in the art, the receivers 20, 30 are also referred to as innerreceivers (IRX) and may, for instance, be implemented by a RAKEreceiver. The outputs of the various demodulators 2.1, 2.2, 2.3, 21, 22,25 to 28 and 31 to 33 are indicated by arrows and may be coupled toindividual decoders. In FIG. 4, by way of example and for the sake ofillustrative ease, only a channel decoder 40 for decoding the outputs ofthe DPCH1/FDPCH demodulator 25 and the DPCH2 and DPCH3 demodulators 26,27 is shown. Such channel decoder 40 is also referred to as outerreceiver (ORX) in the art. It is to be noted that the UE 100 maycomprise a number of channel decoders (not shown) with each channeldecoder being configured to decode a specific channel signal receivedfrom one channel demodulator 2.1, 2.2, 2.3, 21, 22, 25 to 28 of the mainreceiver 20 and from one channel demodulator 31 to 33 of the reducedreceiver 30.

FIG. 5 illustrates a more detailed block diagram of one embodiment of UE100. The configuration and operation of UE 100 shown in FIG. 5 issimilar to the configuration and operation of UE 100 shown in FIG. 4. Inview of the similarities, the corresponding description to FIG. 4 isapplicable to FIG. 5, and reiteration is avoided for the sake ofbrevity. However, in FIG. 5, the reduced receiver 30 still includes afull DPCH demodulation capability, namely DPCH1/FDPCH demodulator 34.Such reduced receiver 30 may be employed in, e.g., an HSUPA receiver ifone reuses a standard DPCH1/FDPCH demodulator unit rather than a(fractional) FDPCH demodulator (although a FDPCH demodulator would besufficient in HSUPA).

In this case, only one or more of the control channels like PCCPCHand/or SCCPCH of the second radio network NW2 are transferred via dataconnection 4 to the full main receiver 20. The DPCH of the second radionetwork NW2 may be demodulated in the DPCH1/FDPCH demodulator 34 of thereduced receiver 30.

Depending on the availability of ORX capability for the reduced receiver30, the UE 100 may include an additional channel decoder 41 (ORX) fordecoding the output of the DPCH1/FDPCH demodulator 34 of the reducedreceiver 30 as shown in FIG. 5. Otherwise, the output of the DPCH1/FDPCHdemodulator 34 may be routed to an input of the channel decoder 40 (ORX)which is coupled to the DPCH demodulators 25, 26, 27 of the mainreceiver 20 and is also used to decode the DPCH of the first network NW1(this case is not illustrated in FIG. 5).

FIG. 6 is a flowchart of an embodiment of a method of demodulating userdata of the first and second radio network NW1, NW2 in a mobilecommunications radio receiver. This method may be performed by UE 100 asshown in FIGS. 3 to 5, for example.

As already described above, a first down-converted signal S1 from aradio signal received from a first radio network NW1 and a seconddown-converted signal S2 from a radio signal received from a secondradio network NW2 are generated at A1 and A2, respectively. Thus, thereare two active data connections established with the first and secondnetwork NW1, NW2. For instance, as shown in FIGS. 4 and 5, RF stages 1.1and 1.2 may be used to concurrently generate down-converted signals S1and S2, respectively.

At A3, a dedicated user data channel of the first radio network NW1based on the first down-converted signal S1 and a dedicated user datachannel of the second radio network NW2 based on the seconddown-converted signal S2 are demodulated in parallel. Exemplaryimplementations of an UE for concurrently demodulating the two user datachannels in respective DPCH demodulators are illustrated by way ofexample in FIGS. 4 and 5.

At A4, a common control channel of the first radio network NW1 based onthe first down-converted signal S1 and a common control channel of thesecond radio network NW2 based on the second down-converted signal S2are demodulated in a time multiplex operation. Exemplary implementationsof an UE for demodulating the at least two common control channels byshared hardware are illustrated by way of example in FIGS. 4 and 5.

Thus, resource (or hardware) sharing is used between the main andreduced receivers 20, 30, which requires mainly some additional datarerouting and control functions such as e.g. control of the multiplexoperation. The control functions may be implemented in firmware. Thatway, it is possible to receive two DPCH from two different radionetworks NW1, NW2 without any major hardware additions to a standarddual-cell HSUPA receiver.

According to another aspect, discontinuous reception (DRX) cycles ofcontinuous packet connectivity (CPC) on the first network NW1 and on thesecond network NW2 are used to maintain active connections with bothnetworks NW1, NW2 in parallel. FIGS. 7 to 9 are timing diagramsillustrating various scenarios of parallel reception of two CPC on thefirst network NW1 and on the second network NW2.

With CPC an UE can have an active connection with a network, but if nodata is sent the UE only checks in certain intervals if data isavailable. In between these checks the UE can be turned off to savepower. The intervals between these discontinuous reception (DRX)instances in CPC are referred to as CPC DRX cycles. CPC is a recentlyintroduced feature of UMTS.

FIG. 7 illustrates the timing of a first CPC connection between an UEand the first network NW1 and a second CPC connection between the (same)UE and the second network NW2. The time spans of the DRX instancesduring which the UE checks whether data is available on the firstnetwork NW1 are indicated by C1, C2, C3, . . . , Cn, Cn+1 in the upperrow of FIG. 7. Similarly, the time spans of the DRX instances duringwhich the UE checks whether data is available on the second network NW2are indicated by C1, C2, C3, . . . , Cn, Cn+1 in the lower row of FIG.7. The horizontal axis corresponds to time.

Considering, e.g., the first network NW1, the demodulator of the UE canbe turned off during the CPC DRX cycles between the DRX instances C1,C2, C3, . . . , Cn, Cn+1 shown in the upper row of FIG. 7 to save power.Here, it may be temporarily turned on during these periods in order tolisten at the DRX instances of the second network NW2 to notificationson available date on the second network NW2 as illustrated in the lowerrow of FIG. 7.

In one embodiment, if the second network NW2 is operated on a differentfrequency band f2 than the frequency band f1 used by the first networkNW1, see FIG. 1, the UE has to be tuned to the second frequency band f2upon activation during the CPC DRX cycles of the first network NW1. Inanother embodiment, if the first and second networks NW1 and NW2 operateon the same frequency band f1, see FIG. 2, the UE may not be tuned toanother frequency band when activated during the CPC DRX cycles of thefirst network NW1 to listen to CPC activity on the second network NW2.

More specifically, FIG. 7 illustrates a case with no CPC activity onboth networks NW1, NW2. Further, the (time spans of the) DRX instancesC1, C2, C3, . . . , Cn, Cn+1 during which the UE is turned on and bothnetworks NW1, NW2 are checked for available data do not overlap in time.More specifically, the DRX instances C1, C2, C3, . . . , Cn, Cn+1 of thesecond network NW2 fall completely into the time gaps (DRX cycles)between the DRX instances C1, C2, C3, . . . , Cn, Cn+1 of the firstnetwork NW1. Therefore, no conflicts will occur, and both CPCconnections can be supported and kept up in parallel by (optional)alternating down-conversion and alternating demodulation of NW1 and NW2signals.

FIG. 8 illustrates a case of CPC activity (i.e. downlink data transferbeyond the CPC notifications on available data transmitted during thecyclic DRX instances) on the second network NW2. The CPC activity occursdirectly after the data available check during DRX instance C2 on thesecond network NW2 yielded a positive result. Thereafter, a period ofCPC activity, i.e. an active continuous downlink user data transfer mayoccur on network NW2.

Since the DRX instance C3 on network NW1 overlaps with the period of CPCactivity on network NW2, it would typically not be possible to listen tothe network notification concerning the data available check at DRXinstance C3 on network NW1, because there is no DRX cycle anymore onnetwork NW2. However, depending e.g. on the setting of the number ofrepetitions of data packets on the second network NW2, it might bepossible to shortly interrupt the data transfer on the second networkNW2 through higher layers (TCP/IP . . . ) and listing instead topossible network notifications on available data at DRX instance C3 ofthe first network NW1.

Listening to a CPC notification (also referred to as CPC status in theart) on the first network NW1 may require only a few time slots.Therefore, even in the case of a continuous active CPC data connectionon the second network NW2 (see FIG. 8), it might be possible to shortlylisten to the first network NW1 during the DRX instances C1, C2, . . . ,Cn, Cn+1 of the first network NW1, because the lost data packets on thesecond network NW2 will probably be repeated. Thus, the user would notnotice the loss of packets on the second network NW2 connection. Evenfor a long ongoing data transfer on the second network NW2, theintentional packet dropping due to listening for CPC status on the firstnetwork NW1 will only result in a slightly lower throughput of theconnection on the second network NW2.

Therefore, still considering the situation illustrated in FIG. 8, adecision may be taken: Either the notification of network NW1 onavailable data at DRX instance C3 is dropped (because the UE keeps onlistening to network NW2) or some data packets on network NW2 areintentionally dropped (because the UE is switched to listen to networkNW1 during the DRX instance C3 to demodulate any possible notificationof network NW1 on available data).

In other words, a first option is that a notification of the firstnetwork NW1 on available data is lost because of the ongoing CPCactivity on the second network NW2. Since such notifications aretypically repeated several times (e.g., the notification may be repeatedafter a delay of one or more CPC DRX cycles at DRX instances C4, . . . ,Cn, Cn+1), there is a high probability to receive at least the delayednotification. The user probably would not notice the short delay untilCPC activity may start on network NW1.

A second option is to prioritize the data available checks at the DRXinstances of the first network NW1 over the continuity of the CPCactivity on the second network NW2. In this case the notification ofavailable data on network NW1 would always be received, whereas somedata packets of the CPC activity on the second network NW2 would bemissed. However, missing some data packets of one or a limited number ofCPC activities would probably not drop the CPC connection on the secondnetwork NW2, because CPC has to take packet loss (e.g. by regularfading) into account. Thus, the drop of some data packets of network NW2could be compensated by higher layer retransmission. Therefore, missingsome data packets of one or a limited number of CPC activities mayprobably only mean a small degradation in throughput of the datatransfer on network NW2.

Therefore, depending on priority settings, either CPC activity on onenetwork or listening to notifications for available data on the othernetwork may be prioritized, and in both cases both operations could beperformed (even though the non-prioritized operation may be delayed fora specific time such as one or more CPC DRX cycles or degraded inthroughput). The priority setting (CPC activity or DRX notificationsprioritized) may be adapted on the basis of the settings of the twonetworks NW1, NW2. By way of example, the priority setting may depend onthe number of repetitions of notifications on available data and/or thenumber of repetitions of lost data packets during an active CPCconnection and/or the length of the CPC DRX cycle.

Of course, as long as the phases of the CPC activity on network NW2 fitinto the DRX cycles of network NW1, with an existing but idle CPCconnection, both the downlink user data on network NW2 and the CPCstatus information on network NW1 may be received by (optional)alternating down-conversion and alternating demodulation of NW1 and NW2signals. In this respect, the case shown in FIG. 8 is similar to thecase shown in FIG. 7.

FIG. 9 illustrates a case of concurrent CPC activity (beyond the CPC DRXcycles) on both networks NW1 and NW2. The CPC activity on network NW2occurs directly after the data available check (positive result) at DRXinstance C2 on network NW2. The CPC activity on network NW1 occursdirectly after the data available check (also positive result) at DRXinstance C3 on network NW1. Since the periods of CPC activities onnetworks NW1 and NW2 overlap in time, a decision may be taken: Eitherone CPC connection is dropped (while the other may be continued) or bothCPC connections are run with e.g. 50% packet loss rate by alternatingthe demodulation of the respective user data channels (and, if only oneRF stage is provided, by alternating the down-conversion of therespective user data signals). The latter approach may result in areduced throughput on both networks NW1 and NW2, but both CPCconnections may survive due to higher layer retransmissions of lost datapackets. This decision (concerning a conflict of concurrent CPCactivities on two or more networks) may also be determined based on apriority setting.

FIG. 10 illustrates an embodiment of an UE 200 configured to be operatedusing one or more of the procedures described above with reference toFIGS. 7 to 9. The UE 200 may comprise one single receiver 20 which maybe identical to the main receiver 20 shown in FIG. 4 or 5. Morespecifically, the receiver 20, which may be an UMTS Rel99 receiver, maycomprise a CPICH demodulator 21 for pilot demodulation, a PICHdemodulator 22, a SCCPCH demodulator 2.2, a second SCCPCH demodulator2.3, a PCCPCH demodulator 2.1, a DPCH1/FDPCH demodulator 25, twoadditional DPCH demodulators 26, 27 and a HSUPA demodulator 28. Theoutputs of the various demodulators 2.1, 2.2, 2.3, 21, 22, 25 to 28 areprovided to a channel decoder 40 (ORX). The channel decoder 40 maycontain for each channel a respective channel decoder to decode thespecific channel signal received from one channel demodulator 2.1, 2.2,2.3, 21, 22, 25 to 28 of the receiver 20.

The UE 200 may comprise a single-band RF unit 1, which can be tuned tothe frequency bands f1 and f2 in a sequential manner, but which can notdown-convert the frequency bands f1 and f2 concurrently. The single-bandRF unit 1 may be controlled by a control unit 50. The control unit 50 isconfigured to switch the single-band RF unit 1 to either generate thefirst down-converted signal S1 from the first network NW1 or to generatethe second down-converted signal S2 from the second network NW2. Thereceiver 20 is informed by the control unit 50 on this selection.

In one embodiment the receiver 20 of UE 200 is configured to demodulateonly one of the first and second down-converted signals S1, S2 at atime. In particular, for example, only one user data signal isdemodulated at a time. Thus, the receiver 20 may include, e.g., only onesingle CPICH demodulator 21 for pilot demodulation and/or only onesingle PICH demodulator 22 for PI demodulation and/or only one singlePCCPCH demodulator 2.1.

The UE 200 may further comprise a priority selection unit 60. In oneembodiment the priority selection unit 60 is configured to select apriority setting in case of conflicting notifications on available dataand CPC DRX activity on networks NW1 and NW2 as explained in conjunctionwith FIG. 8 and/or in case of conflicting CPC DRX activities on networksNW1 and NW2 as explained in conjunction with FIG. 9.

It is to be noted that the control unit 50 and/or the priority selectionunit 60 may be implemented in dedicated hardware or in software(firmware). If the control unit 50 and/or the priority selection unit 60are implemented in software, the embodiments described in FIGS. 7 to 10may not require any hardware changes to existing UEs. They do not evenrequire a dual-band/dual-cell RF unit 1. The embodiments described inFIGS. 7 to 10 may work on every single-band CPC capable hardware andallow a high chance of supporting two or more CPC connections on two ormore networks NW1, NW2, . . . , at the same time. The procedures ofoperating such single-band CPC capable hardware in accordance with thedescription herein may be implemented in the firmware of the UE 200.

According to FIG. 11, the UE 200 may operate as follows: A firstdown-converted signal S1 from a radio signal received from a firstnetwork NW1 is generated at B1. This first down-converted signal S1 isdemodulated during (at least one of) the DRX instances of a CPCconnection with the first radio network NW1 at B2. Further, a seconddown-converted signal S2 from a radio signal received from a secondradio network NW2 is generated at B3. This second down-converted signalS2 is demodulated during a time gap between the DRX reception instances.

Thus, during the time gap (DRX cycle period) between consecutive DRXinstances, the demodulation and/or generation of the firstdown-converted signal S1 may be stopped and the demodulation and/orgeneration of the second down-converted signal S2 from a radio signalreceived from the second network NW2 may be started.

It is to be noted that the reception of speech or data via two activeconnections with two networks as described above in all embodiments canbe done in any RAT (Radio Access Technology) receivers. By way ofexample, in case of one 3G (third generation) and one 2G (secondgeneration) connection, each receiver chain may receive separately thecorresponding 2G and 3G user data information. Thus, the first networkNW1 and/or the second network NW2 may each be a 2G network, a 3G networkor e.g. a LTE network, and any combinations of such different networksare feasible.

The methods, aspects and embodiments described herein all relate to DSDTscenarios, where two connections with two different networks NW1, NW2are considered. Further, also a combination and interaction with othertypes of Dual-SIM capabilities, for instance DSDS(Dual-SIM-Dual-Standby), where both receiver chains are in a standbymode (i.e. with no active connection on any one of the networks NW1,NW2), or DSST (Dual-SIM-Single-Transport), where a paging from onenetwork may be received while having an active connection with the othernetwork, are possible. Further, the methods, aspects and embodimentsdescribed herein can be extended to three or more networks and/or theycan be combined.

Further, it is to be noted that in all aspects and embodiments describedherein, the UEs 100 and 200 may be configured for using HSDPA and HSUPA.

In addition, while a particular feature or aspect of an embodiment ofthe invention may have been disclosed with respect to only one ofseveral implementations, such feature or aspect may be combined with oneor more other features or aspects of the other implementations as may bedesired and advantageous for any given or particular application. Thisapplication is intended to cover any adaptations or variations of thespecific embodiments discussed herein, and the invention is intended tobe limited only by the claims and the equivalence thereof.

What is claimed is:
 1. A method of demodulating user data in a mobilecommunications radio receiver, comprising: generating a firstdown-converted signal from a radio signal received from a first radionetwork; generating a second down-converted signal from a radio signalreceived from a second radio network; demodulating in parallel adedicated user data channel of the first radio network based on thefirst down-converted signal and a dedicated user data channel of thesecond radio network based on the second down-converted signal; anddemodulating in a time multiplex operation a common control channel ofthe first radio network based on the first down-converted signal and acommon control channel of the second radio network based on the seconddown-converted signal.
 2. The method of claim 1, wherein the dedicateduser data channels of the first and second radio networks aredemodulated concurrently by at least two Dedicated Physical Channeldemodulators.
 3. The method of claim 1, wherein a common control channelof the first radio network and a common control channel of the secondradio network are demodulated by one shared common control channeldemodulator.
 4. The method of claim 1, wherein control data of thecommon control channel of the first radio network contained in the firstdown-converted signal is coupled to a common control channeldemodulator, control data of the common control channel of the secondradio network contained in the second down-converted signal is coupledto the common control channel demodulator, and the common controlchannel demodulator is operable in the time multiplex operation.
 5. Themethod of claim 3, further comprising: generating channel estimatesbased on the first down-converted signal; generating channel estimatesbased on the second down-converted signal; and inputting the channelestimates based on the first down-converted signal and the channelestimates based on the second down-converted signal to the shared commoncontrol channel demodulator.
 6. A mobile communications radio receiverfor multiple radio network operation, comprising: an RF unit configuredto generate a first down-converted signal from a radio signal receivedfrom a first radio network and a second down-converted signal from aradio signal received from a second radio network; a first user datachannel demodulator configured to demodulate a first dedicated user dataphysical channel contained in the first down-converted signal and asecond user data channel demodulator configured to demodulate a seconddedicated user data physical channel contained in the seconddown-converted signal; wherein the first and second user data channeldemodulators are configured to demodulate the first and second user dataphysical channels in parallel; and a control channel demodulatorconfigured to demodulate in a time-multiplex operation a common controlchannel of the first radio network based on the first down-convertedsignal and a common control channel of the second radio network based onthe second down-converted signal.
 7. The mobile communications radioreceiver of claim 6, wherein the RF unit comprises: a first RFdown-converter configured to generate the first down-converted signal;and a second RF down-converter configured to generate the seconddown-converted signal.
 8. The mobile communications radio receiver ofclaim 6, wherein the mobile communications radio receiver is configuredto receive one or more of a Common Pilot Channel, a Fractional DedicatedPhysical Channel, a Relative Grant Channel, a Hybrid ARQ IndicatorChannel and an Absolute Grant Channel.
 9. A mobile communications radioreceiver for multiple radio network operation, comprising: an RF unitconfigured to generate a first down-converted signal from a radio signalreceived from a first radio network and a second down-converted signalfrom a radio signal received from a second radio network; a firstreceiving unit comprising a first user data channel demodulatorconfigured to demodulate a first dedicated user data physical channelcontained in the first down-converted signal and a control channeldemodulator configured to demodulate in a time-multiplex operation acommon control channel of the first radio network based on the firstdown-converted signal and a common control channel of the second radionetwork based on the second down-converted signal; and a secondreceiving unit comprising a second user data channel demodulatorconfigured to demodulate a second dedicated user data physical channelcontained in the second down-converted signal; wherein the first andsecond user data channel demodulators are configured to demodulate thefirst and second dedicated user data physical channels in parallel. 10.The mobile communications radio receiver of claim 9, further comprising:a first data connection configured to couple control data contained inthe second down-converted signal to the control channel demodulator ofthe first receiving unit.
 11. The mobile communications radio receiverof claim 9, wherein the second receiving unit comprises no controlphysical channel demodulator for demodulating any common controlphysical data.
 12. The mobile communications radio receiver of claim 9,further comprising: a first outer receiver configured to receive anoutput of the first receiving unit.
 13. The mobile communications radioreceiver of claim 9, further comprising: a second outer receiverconfigured to receive an output of the second receiving unit.
 14. Themobile communications radio receiver of claim 9, further comprising: achannel estimator configured to generate channel estimates based on thesecond down-converted signal, and a second data connection configured tocouple the channel estimates from the channel estimator to an input ofthe first receiving unit.
 15. The mobile communications radio receiverof claim 14, wherein the channel estimator comprises a pilot channeldemodulator contained in the second receiving unit.
 16. The mobilecommunications radio receiver of claim 9, wherein the first receivingunit is an UMTS Rel99 receiver.
 17. The mobile communications radioreceiver of claim 9, wherein the second receiving unit is a reducedreceiver comprising only demodulators for demodulating one or more of aCommon Pilot Channel, a Fractional Dedicated Physical Channel, aRelative Grant Channel, a Hybrid ARQ Indicator Channel and an AbsoluteGrant Channel.